Avis - Not doing as they say!!!!

I made a booking with Avis to rent a car for 8 days. I made the payment using my card. When I received my documentation it stated that the drivers card must be presented when car is collected. The booking was made in my husbands name. This is what is stated on their documentation that they sent me. (Avis South Africa does not accept debit cards. If you have prepaid using a debit card or a credit card which is not in the name of the driver please contact Customer Services on ***/ +27 11 ********** to have the method of payment changed. ) When I phoned them to explain I want to change the card number (because its the same account) they informed me that I need to pay R400 and something rand to add a driver or I need to cancel the whole transaction and book again. This is unacceptable when it clearly states on their documentation that I can phone them to change the method of payment!!! I am very disappointed in Avis. I am very sorry at this stage that I used them. Will not be using them in the future.